diff --git a/harness/temporalHelpers.js b/harness/temporalHelpers.js
index 984902aa7b5..dfbffd776ee 100644
--- a/harness/temporalHelpers.js
+++ b/harness/temporalHelpers.js
@@ -8,6 +8,114 @@ features: [Symbol.species, Symbol.iterator, Temporal]
 ---*/
 
 var TemporalHelpers = {
+  /*
+   * assertDuration(duration, years, ...,  nanoseconds[, description]):
+   *
+   * Shorthand for asserting that each field of a Temporal.Duration is equal to
+   * an expected value.
+   */
+  assertDuration(duration, years, months, weeks, days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds, description = "") {
+    assert(duration instanceof Temporal.Duration, `${description} instanceof`);
+    assert.sameValue(duration.years, years, `${description} years result`);
+    assert.sameValue(duration.months, months, `${description} months result`);
+    assert.sameValue(duration.weeks, weeks, `${description} weeks result`);
+    assert.sameValue(duration.days, days, `${description} days result`);
+    assert.sameValue(duration.hours, hours, `${description} hours result`);
+    assert.sameValue(duration.minutes, minutes, `${description} minutes result`);
+    assert.sameValue(duration.seconds, seconds, `${description} seconds result`);
+    assert.sameValue(duration.milliseconds, milliseconds, `${description} milliseconds result`);
+    assert.sameValue(duration.microseconds, microseconds, `${description} microseconds result`);
+    assert.sameValue(duration.nanoseconds, nanoseconds, `${description} nanoseconds result`);
+  },
+
+  /*
+   * assertPlainDate(date, year, ..., nanosecond[, description[, era, eraYear]]):
+   *
+   * Shorthand for asserting that each field of a Temporal.PlainDate is equal to
+   * an expected value. (Except the `calendar` property, since callers may want
+   * to assert either object equality with an object they put in there, or the
+   * result of date.calendar.toString().)
+   */
+  assertPlainDate(date, year, month, monthCode, day, description = "", era = undefined, eraYear = undefined) {
+    assert(date instanceof Temporal.PlainDate, `${description} instanceof`);
+    assert.sameValue(date.era, era, `${description} era result`);
+    assert.sameValue(date.eraYear, eraYear, `${description} eraYear result`);
+    assert.sameValue(date.year, year, `${description} year result`);
+    assert.sameValue(date.month, month, `${description} month result`);
+    assert.sameValue(date.monthCode, monthCode, `${description} monthCode result`);
+    assert.sameValue(date.day, day, `${description} day result`);
+  },
+
+  /*
+   * assertPlainDateTime(datetime, year, ..., nanosecond[, description[, era, eraYear]]):
+   *
+   * Shorthand for asserting that each field of a Temporal.PlainDateTime is
+   * equal to an expected value. (Except the `calendar` property, since callers
+   * may want to assert either object equality with an object they put in there,
+   * or the result of datetime.calendar.toString().)
+   */
+  assertPlainDateTime(datetime, year, month, monthCode, day, hour, minute, second, millisecond, microsecond, nanosecond, description = "", era = undefined, eraYear = undefined) {
+    assert(datetime instanceof Temporal.PlainDateTime, `${description} instanceof`);
+    assert.sameValue(datetime.era, era, `${description} era result`);
+    assert.sameValue(datetime.eraYear, eraYear, `${description} eraYear result`);
+    assert.sameValue(datetime.year, year, `${description} year result`);
+    assert.sameValue(datetime.month, month, `${description} month result`);
+    assert.sameValue(datetime.monthCode, monthCode, `${description} monthCode result`);
+    assert.sameValue(datetime.day, day, `${description} day result`);
+    assert.sameValue(datetime.hour, hour, `${description} hour result`);
+    assert.sameValue(datetime.minute, minute, `${description} minute result`);
+    assert.sameValue(datetime.second, second, `${description} second result`);
+    assert.sameValue(datetime.millisecond, millisecond, `${description} millisecond result`);
+    assert.sameValue(datetime.microsecond, microsecond, `${description} microsecond result`);
+    assert.sameValue(datetime.nanosecond, nanosecond, `${description} nanosecond result`);
+  },
+
+  /*
+   * assertPlainMonthDay(monthDay, monthCode, day[, description]):
+   *
+   * Shorthand for asserting that each field of a Temporal.PlainMonthDay is
+   * equal to an expected value. (Except the `calendar` property, since callers
+   * may want to assert either object equality with an object they put in there,
+   * or the result of monthDay.calendar.toString().)
+   */
+  assertPlainMonthDay(monthDay, monthCode, day, description = "") {
+    assert(monthDay instanceof Temporal.PlainMonthDay, `${description} instanceof`);
+    assert.sameValue(monthDay.monthCode, monthCode, `${description} monthCode result`);
+    assert.sameValue(monthDay.day, day, `${description} day result`);
+  },
+
+  /*
+   * assertPlainTime(time, hour, ..., nanosecond[, description]):
+   *
+   * Shorthand for asserting that each field of a Temporal.PlainTime is equal to
+   * an expected value.
+   */
+  assertPlainTime(time, hour, minute, second, millisecond, microsecond, nanosecond, description = "") {
+    assert(time instanceof Temporal.PlainTime, `${description} instanceof`);
+    assert.sameValue(time.hour, hour, `${description} hour result`);
+    assert.sameValue(time.minute, minute, `${description} minute result`);
+    assert.sameValue(time.second, second, `${description} second result`);
+    assert.sameValue(time.millisecond, millisecond, `${description} millisecond result`);
+    assert.sameValue(time.microsecond, microsecond, `${description} microsecond result`);
+    assert.sameValue(time.nanosecond, nanosecond, `${description} nanosecond result`);
+  },
+
+  /*
+   * assertPlainYearMonth(yearMonth, year, month, monthCode[, description[, era, eraYear]]):
+   *
+   * Shorthand for asserting that each field of a Temporal.PlainYearMonth is
+   * equal to an expected value. (Except the `calendar` property, since callers
+   * may want to assert either object equality with an object they put in there,
+   * or the result of yearMonth.calendar.toString().)
+   */
+  assertPlainYearMonth(yearMonth, year, month, monthCode, description = "", era = undefined, eraYear = undefined) {
+    assert(yearMonth instanceof Temporal.PlainYearMonth, `${description} instanceof`);
+    assert.sameValue(yearMonth.era, era, `${description} era result`);
+    assert.sameValue(yearMonth.eraYear, eraYear, `${description} eraYear result`);
+    assert.sameValue(yearMonth.year, year, `${description} year result`);
+    assert.sameValue(yearMonth.month, month, `${description} month result`);
+    assert.sameValue(yearMonth.monthCode, monthCode, `${description} monthCode result`);
+  },
   /*
    * Check that any calendar-carrying Temporal object has its [[Calendar]]
    * internal slot read by ToTemporalCalendar, and does not fetch the calendar